1. Field of the Invention
The invention relates to a wrist watch having a glass rim.
2. Description of the Prior Art
It has been a general practice in conventional wrist watches having a movement inserted within a glass rim for fixing the glass rim by means of machine screws.
FIG. 3 is a view illustrating the construction of a conventional wrist watch in which a glass rim is fixed by means of machine screws. In the conventional wrist watch, a female thread portion 21a is provided on an outer periphery of a waterproof packing 40 interposed between a glass rim 21 and a barrel 31. Accordingly, the distance from the outer diameter D1 of the dial plate to the outer diameter of the glass rim 21 is the sum of a dial plate bearing surface width A, a width D of a wall to which the waterproof packing 40 is mounted, a width B of a box for the waterproof packing 40, a wall thickness C of the box, a dimension E of the female thread portion, and a width F of bearing surfaces of the glass rim 21 and the barrel 31, that is, (A+D+B+C+E+F).
FIG. 6 is a cross sectional view showing a construction for fixation of a chamfer-type glass rim in a conventional wrist watch. A glass rim 22 has a chamfer portion 22a with an interference between it and a barrel 32, and is fixed to the barrel 32 by the interference. Accordingly, stress at the time of mounting is applied to fixed portions of the glass rim 22 and a glass 70 to make the same susceptible of deformation, so that the adhesive structure of the glass 70 to the glass rim 22 cannot be used due to deterioration in adhesive quality and so the glass 70 is fixed to the glass rim 22 through a plastic packing 70a having a chamfer. Also, since the glass rim 22 and the barrel 32 are fixed to each other by means of the chamfer portion 22a, they are restricted to a round configuration in plan, and are used under such design restrictions that in view of maintenance of the quality of fixing of the glass rim 22, the glass rim 22 is formed from a material except a precious metal or increased as a whole in wall thickness.
Conventional wrist watches have a problem in that since machine screws are arranged on an outer periphery of a waterproof packing in order to maintain the barrel of the watch casing and the glass rim waterproof, a width from an external shape of a glass portion of the glass rim to an external shape of the glass rim is enlarged, and thus it is difficult to make the glass rim thin. Therefore, although a certain design quality is demanded, it has been difficult under considerable design restrictions to obtain a desired design.
Also, wrist watches, in which a glass rim is fixed by mounting a portion of the glass rim directly to a barrel of a watch casing with a chamfer, cause a problem that in order to maintain the quality of opening and closing the glass rim, the glass rim is required to have a width and thickness for ensuring the strength of a glass rim material. Further, with wristwatches intended for accessories and ornaments, a precious metal material is frequently used to make a glass rim but a usable material is limited due to the material strength and dimensional restrictions, thus causing a problem that a material is restricted. Therefore, for preservation of strength, the glass rim must be made considerable in thickness and width, so that it is not possible to make the glass rim thin and to make a thin-type wrist watch, which is wanted by users, and development of design quality is sought after with difficulty.
Under these circumstances, with a chamfer-type glass rim, stress at the time of mounting possibly leads to coming-off of an adhesive portion in quality in the case where a glass is fixed to the glass rim by an adhesive, so that such way of fixation is less implemented and is made little use of. Also, at the time of maintenance of a movement with hands and a dial plate, opening and closing of the glass rim entails degradation in quality of mounting, and so the way of fixation is not accepted in the market.
Thereupon, the invention has been devised in view of the above, and has its object to provide a wrist watch, in which a glass rim is reduced in width and in thickness, restrictions on materials for the glass rim are relaxed, and a glass rim of a high design quality having a demand in the market is fixed.
The invention provides a wrist watch comprising a glass rim for fixation of a glass, a barrel which contacts with an underside of the glass rim to contain therein a movement, a first packing provided between the glass rim and the barrel to ensure a waterproof seal between the glass rim and the barrel, and screws disposed inside of the packing to fix the barrel and the glass rim together.
The screws are disposed inside of the first packing so that it is possible to provide a glass rim of a small diameter while ensuring a waterproof seal.
Also, according to the invention, the screws have a second packing in an optional position on an external shape thereof.
The second packing is provided on the screws to enable providing a glass rim of a small diameter.
Also, with the wrist watch according to the invention, the barrel has screw recesses, into which the screws are inserted, and the second packings and the screw recesses engage with each other.
The screw hole and the second packing engage with each other to thereby enable ensuring water-proofness on the screw hole.
Further, with the wrist watch, the glass rim comprises a dial-plate bearing surface, which bears a dial-plate, a female thread portion adapted to engage with the screws, a packing box, which bears the first packing, and a bearing surface, which bears the barrel.
Thereby, it is possible to reduce a width of the glass rim.
Also, in the construction composed of a glass rim, a barrel and a back cover, the screws not only latch the glass rim but also may be used for fixation of the back cover as well as latching of the glass rim.